This is for one of my family members pls help

What is the best way to answer questions with a x expression in the question. for example 3x + 10x=?

In stepmber, daniel and justin opened a business. during their first three months of business, their average monthly profit was $51. if during their first month, they lost $29, and during their second month, they gained $115, what was their profit or loss for their third plzzz i will give you 299 points

Apasta salad was chilled in the refrigerator at 35° f overnight for 9 hours. the temperature of the pasta dish dropped from 86° f to 38° f. what was the average rate of cooling per hour?